ing to the local situation. Changes in policy and patterns of consumption will be necessary in many places if water supplies are to be adequate and cheap. For some time it has been fashionable to say that although the outlook for resource quantities can be moderately optimistic even in the poor places, the prospects are overwhelming that everywhere the quality of the resource base itself will deteriorate at an alarming and accelerating rate. Comprehensive statistics which would indicate the trends in the condition of the natural environment of land, water, and air are hard to come by. Environmental Quality It is a matter of common observation that environmental quality in the great cities of the world, both in the developed and less developed regions, has deteriorated and that air pollution, water pollution, and landscape degradation have increased. At the same time planning and investment in preventive and treatment measures have improved so that human health and life expectancy may be more favorable now than at any time in the past. However, we must not forget that health conditions in any earlier period used for comparison were wretched. We have tried to present statistically the two basic and overriding trends which, at least in an incipient way, make for pollution and environmental quality problems. We have arrayed a number of countries from the different regions of the world on scatter diagrams which indicate that the more densely populated and the more highly industrialized countries have the incipient conditions for greater environmental pollution. Less industrialized and less densely populated countries can gauge from the diagrams their own likely path toward pollution as they grow in population and industry. Trends in population density and production (or income) per capita are the general indicators of incipient pollution; statistics on fuel consumption, newsprint consumption, and use of DDT and pesticides are among the more specific indicators. All of these are associated with higher levels of economic development. Whether the developed countries are actually experiencing more—or less-environmental pollution than less developed ones is a complex question. If investment and other efforts to abate or prevent pollution were the same in both, then environmental conditions would no doubt be worse in the more developed places. As things stand now, however, people in the less developed regions seem to be worse off. Their water supplies are usually less pure, both solid waste and sewage problems are severe, housing conditions very bad, and public health levels low. Densely populated urban slums and poverty-stricken rural villages alike are characterized by physical environments of generally poor quality, although specific conditions vary from one situation to another. In the large cities of less developed countries air pollution and congestion wills.red to be incomplete.